SOME  FACTORS  AFFECTING  WATER  ABSORPTION  AND 
GERMINATION  OF  SEED  CORN 


BY 


GEORGE  HARLAN  DUNGAN 
B.  S.  University  of  Illinois,  1917 


THESIS 


Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 


Degree  of 

MASTER  OF  SCIENCE 
IN  BOTANY 


IN 


THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 


1921 


cu  , 

tu 

CO 


\^l\  UNIVERSITY  OF  ILLINOIS 


W3\ 


THE  GRADUATE  SCHOOL 


19 


1 HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 
SUPERVISION  RY  George  Harlan  Dung  an 


ENTITLED Soma-  Factors 

Germination  of  Seed  Horn 


BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 
THE  DEGREE  OF Master  of  Science 


Recommendation  concurred  in* 


Committee 


on 


Final  Examination* 


*Required  for  doctor’s  degree  but  not  for  master’s 


X?  Ky  ■■ rb>  ft;  _ - rg. 


■ 


TABLE  OF  COII TEATS 


I.  Introduction  1 

II.  Literature  3 

III.  Materials  and  Methods  7..... , 5 

IV.  Results 9 

Influence  of  Stage  of  Harvesting  Corn  on 
Its- Water  Absorption  and  Germination.......  9 

Effect  of  Initial  Moisture  in  Corn  on  Its 
Water  Absorption  and  Germination... 13 

Composition  of  the  Corn  Kernel  and  Its 
Water  Absorption. .16 

Two  Types  and  Twp  Varieties  of  Corn 
Soaked  in  Water  at  Constant  Temperature 
and  for  Four  Different  Periods  and  Planted 
in  the  Field  for  Performance  Studie s. ...... 25 

V.  Conclusion 33 

VI . Acknowledgements. 34 

VII.  References  Cited 35 


Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/somefactorsaffecOOdung 


SOME  FACTORS  APR EC TING  WATER  ABSORPTION 


AND  GERMINATION  OP  SEED  CORN. 

I.  Introduction 

Agricultural  Experiment  Stations  and  teachers 
of  Agriculture  throughout  the  corn  belt  are  quite  unan- 
imous in  their  advice  to  the  farmer  concerning  the  se- 
lection and  care  of  seed  corn.  The  man  on  the  farm 

alter 

is  urged  to  harvest  seed  corn  while  it  is  in  the  dent 
stage,  before  the  first  killing  frost,  and  to  store  it 
under  conditions  that  insure  rapid  curing.  During  the 
curing  process  the  temperature  must  be  controlled  so 
that  it  will  not  fall  to  or  below  the  freezing  point; 
and  provision  must  be  made  for  proper  ventilating  facil- 
ities that  will  allow  a rapid  and  effective  circulation 
of  air.  After  the  moisture  in  the  corn  has  been  reduced 
to  12  or  14  per  cent,  the  manner  of  storage  is  immater- 
ial so  long  as  the  ears  are  protected  from  direct  expo- 
sure to  the  weather.  Just  how  long  it  will  take  for 
corn  to  reach  a moisture  content  of  12  to  14  per  cent 
is  difficult  for  the  farmer  to  determine.  To  be  sure 
of  complete  curing  he  has  been  usually  leaving  his  corn 
in  the  curing  house  unduly  long  and  thus  reducing  the 
moisture  content  below  12  or  14  per  cent.  This  contin- 
ued curing  no  doubt,  injures  the  grain  as  seed  corn. 


One  of  the  topics  for  the  present  investigation  is  to 

find  the  effect  that  time  of  harvesting  and  thorough- 

of  drying 

ness/ has  on  the  grain  used  for  seed. 

It  lias  been  long  understood  that  the  physiolog- 
ical activity  in  seeds  is  controlled  to  a great  degree  by 
the  moisture  in  them.  The  quantity  of  water  present 
in  the  seed  during  the  dormant  or  storage  period  that 
will  give  the  best  growth  and  yield  in  the  field  has 
never  been  definitely  worked  out.  The  federal  system 
of  grading  c or n; promulgated  in  July  1916. has  placed 
the  most  desirable  moisture  content  of  corn  for  safe 
keeping  in  storage  at  14  per  cent  or  below.  The 
grading  of  corn  involves  a determination  of  test  weight 
per  bushel,  per  cent  water  contained  in  the  sample, 
damaged  corn  which  includes  moldy  kernels,  heat  damaged 
grains,  etc.  and  foreign  material  and  cracked  corn. 

Water  in  corn  is  the  most  detrimental  factor  to  its 
safe  preservation  in  storage.  It  lowers  the  specific 
gravity  of  the  corn  and  tends  to  contribute  to  the  con- 
ditions that  develop  mustiness  and  heat  damage.  The 
only  factor  into  which  water  does  not  enter  in  grade 
determination  is  foreign  material  and  cracked  corn.  On 
the  other  hand,  the  absorption  of  water  is  the  initial 
process  in  germination  and  growth.  This  report  pre- 
sents what  was  learned  in  the  laboratory  concerning 
the  rapidity  of  water  imbibition  and  speed  of  germin- 
ation when  corn  of  various  initial  moisture  contents 


“ 


. 


' 


was  used. 


-3- 

Many  farmers  have  observed  that  some  types  and 
varieties  of  corn  sprout  sooner  in  the  field  than  others. 
This  problem  includes  a study  of  two  different  types  of  corn 
and  corn  of  the  same  variety  but  having  different  chemical 
composite on. 

It  has  been  reported  that  the  practice  of  soaking 
corn  in  water  previous  to  planting  is  advantageous,  espec- 
ially if  the  planting  is  done  late.  Some  trials  were 
made  to  get  some  information  on  this  question. 

II.  Literature 

Kiesselbach  and  Ratcliff*  report  that  from  the 
standpoint  of  autumn  freezes  corn  containing  from  15  to 
20  per  cent  of  moisture  is  safe;  and  corn  with  10  to  14 
per  cent  of  moisture  will  stand  the  most  severe  winter 
temperatures  without  injury  to  its  germinative  power.  The 
fatal  minimum  moisture  content  of  protoplasm  is  fixed  by 

p 

Ewart  at  two  or  three  per  cent. 

Water  absorption  by  seeds  is  the  first  step  in 
their  germination.  Atkins  in  his  imbibition  studies 
working  with  beans  and  peas  noted  that  the  rate  at  which 
distilled  water  is  taken  up  is  no  greater  than  that  at 
which  salt  solutions  are  absorbed.  Seeds  placed  in  nor- 
mal sulphuric  acid,  decinormal  iodine,  decinormal  sodium 
chloride  produced  no  concentration  of  these  solutions. 

This  was  taken  to  prove  that  there  is  no  semipermeable 
membrane  in  bean  seed  until  germination  begins  when  the 


-4- 


cell  protoplasm  acts  as  such,  and  that  there  is  no  differ- 
ence in  absorption  between  living  and  dead  seeds  until 
after  germination  when  the  protoplasmic  membrane  is  formed. 
Brown  and  Worley4  worked  with  barley  grains  and  made 
water  absorption  studies  at  three  different  temperatures. 
They  concluded  that  the  velocity  with  which  the  water  is 
absorbed  by  the  seed  is  almost  exactly  an  exponential 
function  of  the  temperature.  This  is  explained  by  presum- 
ing that  cold  water  contains  a relatively  high  proportion 
of  "hydrone"  (0  H2J2  whi0*1  upon  being  warmed  breaks  down 
into  the  simpler  molecules.  It  would  appear  that  only 
these  simpler  molecules  are  directly  assimilated  by  the 
seeds  or  transmitted  by  the  differential  septum.  Shull5 
states  that  it  is  his  conviction  after  a number  of  years 
of  experience  with  absorption  phenomena,  that  absorption 
is  a complex  process  dependent  on  a number  of  factors, 
some  of  which  may  be  external,  but  many  of  which  are  in- 
ternal. His  work  with  Xanthium  seeds  and  split  peas  in- 
dicates that  absorption  is  both  chemical  and  a physical 
process  that  is  not  entirely  dependent  upon  temperature. 

Soaking  seeds  previous  to  planting  often  hastens 
germination.  Increased  crop  yields  have  been  reported  as 
the  result  of  swelling  seeds  in  water.6  Recently  Braun8 
has  shown  that  the  presoak  method  of  seed  treatment  is  an 
effective  means  of  preventing  seed  injury  due  to  chemical 
disinfectants  and  that  this  also  increases  germicidal  ef- 
ficiency. 


\ 


. 


-5- 


The  soaking  of  seed  prior  to  planting  never  has 

had  a wide  practical  application.  However,  when  more  is 

learned  concerning  the  relation  of  temperature  during 

early  growth  and  later  development,  it  may  be  profitable 

to  swell  seeds  at  the  temperature  found  most  desirable  for 

9 

maximum  production.  Walster's  work  with  Oderbrucher  bar- 
ley grown  in  sand  cultures  maintained  at  15  degrees  and 
EO  degrees  centigrade  is  suggestive  in  this  connection. 

The  plants  growing  at  the  lower  temperature  were  much  more 

% 

upright  in  growth  habit,  produced  a greater  proportion  of 
culm  to  leaf,  a greater  proportion  of  skeleton  material 
in  the  leaf  and  a greater  degree  of  lignification  of  con- 
nective tissues  in  both  leaf  and  culm. 

III.  Materials  and  Methods 

The  corn  used  was  largely  of  the  He  id's  Yellow 
Dent  variety  having  medium  rough  indentation.  It  conformed 
very  closely  to  the  type  that  was  considered  as  standard 
by  the  Illinois  Corn  Growers  Association  prior  to  the  adop- 
tion of  the  Utility  Score  Card  in  January,  1921.  Part  of 
this  corn  came  from  Professor  J.  G.  Hosier's  farm,  south 
of  Urbana^ana  part  of  it  was  produced  on  the  Agronomy 
South  Harm  of  the  Agricultural  Experiment  Station. 

Part  of  the  corn  was  harvested  at  three  different 
stages  of  its  development;  viz.,  milk  stage,  dent  stage, 
and  mature  stage.  Corn  was  considered  to  be  in  the  milk 
stage  when  the  content  of  the  kernels  had  changed  from 
its  earlier  watery  form  to  a milky  liquid  having  the  con- 


••  ' 

, 

. 


* 


-6- 


sistency  of  cream.  This  point  ih  the  development  of  the 
grain  of  corn  was  practically  the  same  as  that  desired  by 
users  of  roasting  ears  or  cut  corn  for  the  table.  In  the 
dent  stage  development  had  progressed  until  the  internal 
composition  of  the  kernel  had  the  consistency  of  dough 
and  the  crown  of  the  grain  had  a small  dimple  dent.  The 
husks  were  brown  and  dry,  and  the  stalks  were  still  green. 
Fanners  are  commonly  advised  to  harvest  their  seed  corn 
when  it  is  in  this  period  of  its  development.  The  mature 
samples  were  harvested  at  the  time  the  corn  was  dry  enough 
to  begin  cribbing.  The  kernels  were  completely  dented  and 
dry,  and  the  ears  contained  approximately  20  per  cent  of 
water.  The  ears  were  taken  to  the  greenhouse  and  allowed 
to  dry  at  room  temperature.  During  the  winter  after  all 
the  corn  had  reached  an  approximately  uniform  moisture 
content,  imbibition  and  germination  studies  were  made  at 
a number  of  constant  temperatures. 

For  the  investigation  on  the  influence  of  quanti- 
ty of  initial  moisture  on  the  speed  of  water  absorption 
and  vigor  of  germination,  corn  was  taken  directly  from  a 
crib.  Ears  were  chosen  on  the  basis  of  moisture  content  as 
determined  by  handling  and  visual  appearance,  and  grouped 
into  classes.  Each  class  was  shelled  separately  and  thor- 
oughly mixed  forming  a composite  sample.  A moisture  de- 
termination was  then  made  by  the  Brown  -Puvel  Moisture 
Tester  Apparatus.  It  was  planned  to  obtain  composite  sam- 
ples of  corn  representing  all  grades  from  1 to  Sample  in- 
clusive. The  Federal  Grades  in  respect  to  moisture  are 


- 

1 

. 

■ 

• 

. 

-7- 


as  follows: 


Grade 

designation 

Maximum  moisture  content 

Grade 

1 

14  $ 

Grade 

2 

15.5 

Grade 

3 

17.5 

Grade 

4 

19.5 

Grade 

5 

21.5 

Grade 

6 

23 

Grade 

Sample 

More  than  23$ 

Each  grade  of  corn  was  then  poured  into  a separate  mason 
jar  and  carefully  sealed  to  prevent  further  desiccation. 
Imbibition  studies  were  made  as  soon  as  practicable  to 
avoid  any  deterioration  of  the  corn  in  the  sealed  jars. 
However,  some  of  the  grades  containing  large  quantities  of 
water  fermented  and  rapidly  molded.  Because  of  this  rapid 
deterioration  in  storage  it  was  deemed  advisable  to  collect 
the  samples  of  high  moisture  content  as  they  were  used. 

Pour  ears  each  of  Illinois  High  Protein,  Illinois 
Low  Protein,  Illinois  High  Oil  and  Illinois  Low  Oil  were 
obtained  from  the  one  year  old  seed  stock  of  the  Plant 
Breeding  Division.  Each  ear  of  the  high  and  low  protein 
corn  had  been  analyzed  chemically  and  the  data  giving  the 
amount  of  protein  wets  furnished.  !The  oil  percentage  was 
also  known  for  every  ear  of  the  high  and  low  oil  types. 

The  corn  from  these  ears  was  studied  both  from  the  stand- 
point of  rate  of  imbibition  and  rapidity  and  vigor  of  ger- 


. 


;■ 

. 


-8- 


raination. 

The  seed  that  was  used  in  the  investigation  of  the 
effect  of  presoaking  on  the  growth  and  yield  of  corn,  was 
obtained  from  James  R.  Holbert,  Bloomington,  Illinois.  It 
consisted  of  diseased  and  disease-free  corn  of  Reid's  Yel- 
low Dent  and  Bunk's  Ninety  Day  varieties.  Its  diseased 
condition  and  freedom  from  disease  had  been  determined  by 
Mr.  Holbert  in  germination  tests  on  his  neutral  base  or 

saw  dust  lime  germinator. 

% 

In  the  imbibition  studies  a definite  number  of 
grains  (either  25  or  50)  were  counted  out  and  carefully 
weighed  to  within  one  centigram.  The  weighed  corn  was  then 
poured  into  jelly  glass  jars.  Two  samples  were  prepared  for 
each  of  six  temperature  chambers.  These  chambers  were  main- 
tained at  constant  temperature  - not  varying  as  much  as  one- 
half  a degree  centigrade  day  or  night.  The  temperatures 
used  were  5 degrees,  10  degrees,  15  degrees,  20  degrees, 

25  degrees,  and  30  degrees  centigrade.  When  the  com  was 
placed  into  the  temperature  chambers  it  was  covered  with 
distilled  water  which  had  the  same  temperature  as  the  cham- 
bers. At  the  end  of  the  test  the  water  was  drained  off  and 
the  corn  dumped  onto  a dry  absorbent  towel.  A corner  of 
the  towel  was  folded  over  the  corn  and  rubbed  hurriedly 
for  a few  seconds.  The  corn  was  then  turned  onto  a second 
dry  towel  which  was  also  folded  over  the  kernels  and  rubbed 
until  all  superficial  moisture  on  the  grains  was  removed. 

The  weight  of  the  kernels  was  then  obtained.  Most  of  the 
imbibition  determinations  covered  a twenty-four  hour  period, 


. 

. 


-9- 


but  there  was  one  series  which  was  dried  and  weighed  hourly 
for  twenty-four  hours.  In  order  to  make  the  soaking  periods 
the  same  for  all  samples,  new  samples  for  the  next  day's 
work  were  put  into  the  chamber  as  the  ones  to  be  dried  and 
weighed  were  taken  out.  Water  absorption  calculations  were 
made  with  the  weight  of  water-free  corn  as  the  basis.  Ger- 
mination studies  were  made  on  plaster  of  Paris  blocks.  Slabs 
of  plaster  of  Paris  two  inches  thick  and  eight  inches  square 
were  laid  in  galvanized  iron  pans.  Water  was  poured  over 
these  until  it  came  within  approximately  one-eighth  inch 
of  the  top  of  the  blocks.  Grains  of  corn  were  then  laid 
germs  up  on  the  plaster  of  Paris  slabs.  The  cover  was 
placed  over  the  pan  which  was  set  into  the  temperature 
chamber.  By  this  method  when  the  lid  was  removed  from  the 
pan,  every  step  in  the  germination  process  was  easily  vis- 
ible. 

IY.  Results. 

Influence  of  Stage  of  Harvesting  Corn  on 
Its  Water  Absorption  and  Germination 
The  corn  that  was  harvested  at  different  stages 
in  its  development  had  approximately  reached  the  same  mois- 
ture content  when  the  imbibition  studies  were  made.  The  milk 
stage  corn  had  9.5$  of  water.  The  dent  stage  corn  contained 
10.7$  and  the  completely  mature  grains  10.3$.  The  average 
weight  of  the  kernels  showed  very  striking  differences. 

The  early  picked  corn  weighed  approximately  one  half  as 
much  as  the  mature  corn.  Of  300  kernels  of  corn  the  aver- 
age weight  per  grain  harvested  in  the  milk,  dent,  and  ma- 


, 

. 

. 

- 


, 


- 


. 

. 

' 


Percentage  water  after  24  hour-5  soaking 


-10- 


ture  stages  was  .163,  ,268,  and  .320  grams,  respectively. 
The  amount  of  water  absorbed  in  a twenty-four  hour  period 
by  each  lot  of  corn  appears  below  based  on  the  weight  of 
water-free  corn: 

Table  I.  Water  imbibed  by  corn  harvested  at  3 different 
stages  of  maturity  during  a period  of  24  hours 
soaking  in  water  maintained  at  6 different  con- 
stant temperatures. 


Temperature 

Water 

imbibed  by  corn  harvested  in 

Milk  stage 

'Well  dented  stage 

Mature  stage 

5 degrees  C 

74.130 

64.055 

46.275 

10  degrees  C 

85.160 

68.710 

53.970 

15  degrees  C 

89.905 

70.025 

57.975 

20  degrees  C 

90.075 

71.780 

59.255 

25  degrees  C 

94.385 

72.900 

60.930 

30  degrees  C 

91.465 

72.565 

61.070 

Average 

87.520 

70.006 

56. 589 

It  is  evident  that  early  harvesting  of  corn  influ- 
ences the  rate  of  water  intake.  Seemingly  the  maximum 
capacity  for  water  is  higher  in  immaturely  picked  corn  than 
in  that  gathered  later.  This  is  probably  due  to  the  great- 
er quantity  of  sugars  in  the  earlier  harvested  grain.  The 
"milk”  and  "dent"  corn  absorbed  slightly  less  water  at  30 
degrees  dentfgrade  than  at  25  degrees  centigrade  whereas 
the  mature  corn  increased  its  water  content  at  30  degrees 
centigrade.  The  increase  in  water  absorption  for  each  5 
degree  rise  in  temperature  is  much  more  clearly  shown  in 


-11- 


graph  I than  in  the  table. 

Duplicate  germination  tests  of  50  grains  each  were 

made  of  each  sample  of  corn  on  plaster  of  Paris  blocks  at  1& , 

20,  25  and  30  degrees  centigrade.  Observations  were  made 

daily,  and  records  of  the  progress  of  seedling  development 

taken.  The  grains  that  had  sent  out  a radicle  only,  were 

counted  separately  from  those  that  had  produced  both  a radicle 

and  plumule.  Table  II  summarizes  the  information  collected 

in  these  tests.  The  columns  headed  "r"  give  the  radicles 

only , while  !r  p'  includes  both  the  radicles  and  plumules. 

Table  II.  The  Germination  of  corn  harvested  at  three  dif- 
ferent dates  and  germinated  at  four  different  con- 
stant temperatures. 


Tem- 

pera- 

ture 

Corn 

used 

Av 

arage  percents 

tge  germination  in 

2 

days 

3 

days 

4 

days 

5 

days 

6 

days 

18 

days 

Per  cent 
vitality 

. 

r 

r£ 

r 

rp 

r rp 

r 

rF 

r 

rp 

r 

rp 

15° 

Milk 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Dent 

0 

0 

3 

0 

7 

0 

7 

Mature 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

20° 

Milk 

9 

0 

23 

1 

69 

11 

43 

37 

29 

63 

— 

- 

92 

Dent 

10 

1 

17 

3 

34 

34 

30 

49 

17 

75 

- 

- 

92 

Mature 

1 

1 

10 

12 

36 

26 

22 

46 

11 

83 

- 

- 

94 

25° 

Milk 

17 

0 

35 

4 

48 

32 

24 

62 

22 

66 

* 

88 

Dent 

23 

1 

33 

7 

28 

62 

IS 

78 

9 

88 

- 

- 

97 

Mature 

3 

— 

1 

27 

3 

35 

58 

4 

91 

4 

93 

- 

- 

97 

30° 

Milk 

36 

7 

39 

25 

24 

66 

- 

- 

- 

- 

- 

- 

90 

Dent 

29 

9 

30 

32 

20 

73 

93 

Mature 

27 

0 

36 

20 

15 

81 

— 

- 

- 

- 

- 

96 

-12- 


The  figures  presented  suggest  that  even  though  ex- 
tremely early  harvested  corn  absorbs  water  quickly  and  in 
large  quantities  the  speed  of  germination  during  the  first 
three  days  is  only  slightly  greater  than  in  "dent”  corn. 

Later  the  "milk"  corn  is  overtaken  by  the  more  mature  ker- 
nels which  at  the  end  of  the  test  surpass  it  in  vitality. 

This  lower  vitality  expressed  in  germinati onal  vigor  may 
be  explained  on  the  basis  that  the  immature  corn  had  not 
received  sufficient  or  properly  balanced  translocated 
material  from  the  parent  plant  before  it  was  harvested. 

The  dent  corn  is  more  rapid  in  germination  than  the  mature 
corn,  but  it  is  surpassed  in  viability  by  the  latter. 

It  may  be  noted  that  at  30  degrees  C. the  immature 
corn  had  produced  36  "r's"  and  7 "r  p's"  in  two  days  during 
which  time  the  "dent"  corn  had  sent  out  29  "r's"  and  9 "r  p's" 
and  the  mature  corn  27  "r's”  and  no  "r  p's".  At  the  end 
of  the  third  day  the  "dent"  corn  had  developed  32  plumules 
as  compared  to  25  and  20  for  the  "milk"  and  "mature"  corn, 
respectively.  The  close  of  the  fourth  day  shows  the"mature" 
corn  to  be  much  superior  to  either  of  the  others  and  the 
"dent"  corn  much  better  than  the  "milk"  sample.  The  same 
striking  differences  appear  at  the  end  of  6 days  at  temper- 
atures of  20  and  25  degrees  C,  except  that  at  20  degrees  the 
plumule  production  of  the  milk  corn  does  not  at  any  time 
equal  that  of  that  harvested  later.  This  leads  to  the  con- 
clusion that  low  temperature  favors  root  development  and 
retards  the  growth  of  the  shoot. 


-13- 


Affect  of  Initial  Moisture  in  Corn  on 
Its  Water  Absorption  and  Germination. 

Five  of  the  seven  grades  of  corn  were  used  in  the 
studies  of  imbibition.  The  original  moisture  content  of 
the  samples  and  the  quantity  of  water  taken  up  during  twen- 
ty-four hours  at  the  six  temperatures  appears  in  Table  III. 
The  lower  half  of  the  table  shows  the  amount  of  water  that 
was  absorbed  over  and  above  the  moisture  already  present  in 
the  seed. 


Table  III.  Imbibitional  study  of  corn  containing  different 
amounts  of  initial  moisture. 


Percent 

Percentage 
the  basis  of 
period  of  soa 

moisture  in  corn  calculated  on 
water-free  corn  after  a 24  hour 
king  in  distilled  water  at  - 

Grade 

moisture 

content 

5 

10 

15 

20 

25 

30°  C 

One 

13.9 

34.30 

45.69 

46.49 

49.51 

52.34 

55.03 

Two 

14.2 

43.42 

49.11 

49.41 

53.59 

53.76 

58.89 

Four 

18.3 

42.96 

48.28 

50.12 

54.30 

55.87 

60.38 

Five 

20.2 

41.72 

46.54 

50.15 

53.88 

56.58 

59.93 

Sample 

23.5 

50.02 

54.40 

57.00 

60.55 

61.28 

67.71 

Moisture 

content 

Perc< 

during 

antage  moisture  taken  up  by  the  corn 
a 24  hour  period  at  - 

Grade 

5 

10 

15 

20 

25 

30°  C 

One 

13.9 

21.40 

31.79 

32.59 

35.61 

38.44 

41.13 

Two 

14.2 

29.22 

34.91 

35.21 

39.39 

41.56 

44.69 

Four 

18.3 

24.66 

29.98 

31.82 

36.00 

37.57 

42.08 

Five 

20.2 

21.52 

26.34 

29.95 

33.68 

36.38 

39.73 

Sample 

23.5 

26.52 

30.90 

33.50 

37.05 

37.78 

44.21 

-14- 

It  is  evident  from  a study  of  the  above  data  that 
the  natural  moisture  in  corn  is  not  the  only  factor  or  at 
least  not  the  direct  factor  that  influences  the  quantity  of 
water  absorbed.  The  elements  that  enter  into  the  imbibi- 
tional  process  and  bring  about  wide  differences  in  amount  of 
water  taken  up  at  5 degrees  are  less  potently  operative 
at  30  degrees.  The  corn  containing  14.2#  initial  moisture 
leads  all  of  the  samples  in  amount  of  water  absorbed.  This 
is  followed  by  Sample  grade,  with  grades  one  and  four  run- 
ning close  together.  Grade  five  has  taken  on  the  smallest 
quantity  of  additional  water  of  any  one  of  the  series. 

For  the  germination  phase  of  the  problem  on  the 
influence  of  initial  moisture  on  rapidity  of  seedling  devel- 
opment, three  samples  of  corn  having  a moisture  content  of 
6.1,  12.6  and  19.2  per  cent,  respectively,  were  obtained. 
These  were  germinated  at  10,  20,  25,  and  30  degrees  C. 


« 

. 


. 


-15- 

Table  IV.  Germination  testa  of  corn  oontaining  different 
amounts  of  moisture. 

Case 

Moi3tur 
Content 
of  corn 
used 

<} 

Average  percentage  germination  at  end  of 

Total 

% 

Vital- 

ity 

2 

days 

3 

days 

4 

days 

5 

days 

6 

days 

7 

days 

8 

days 

18 

days 

r 

rp 

r 

rp 

r 

rp 

r 

rp 

r 

rp 

r 

rp 

r 

rp 

r 

rp 

10° 

6.1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

12.6 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

1 

1 

19.2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

3 

10 

o 

o 

<M 

6.1 

0 

0 

0 

0 

0 

0 

0 

0 

7 

0 

28 

3 

45 

7 

1 

95 

96 

12.6 

0 

0 

0 

0 

0 

0 

0 

1 

46 

4 

66 

14 

59 

30 

2 

97 

99 

19.2 

0 

0 

0 

0 

2 

0 

12 

1 

33 

3 

30 

9 

27 

18 

3 

77 

80 

25° 

6.1 

3 

0 

17 

0 

55 

32 

- 

— 

> 

* 

— 

87 

12.6 

44 

0 

73 

12 

20 

80 

100 

19.2 

55 

0 

61 

19 

14 

72 

86 

03 

o 

O 

6.1 

91 

0 

29 

63 

92 

12.6 

97 

0 

9 

88 

• 97 

19.2 

B5 

0 

12 

73 

85 

At  20°  after  5 days  the  ”19.2  per  cent”  c 
produced  12  ”r's"  and  1 ”r  p”t  the  ”12.6  per  cenl 
”r's”  and  1 ”r  p”,  and  the  ”6.1  per  cent”  corn  h£ 
gun  to  germinate.  This  behavior  would  suggest  ti 
initial  moisture  in  corn  will  give  rise  to  rapid 
tion.  The  advantage  the  more  moist  sample  had  is 
however,  at  the  close  of  the  sixth  day.  The  resu 
tained  after  days  at  25  degrees  are  in  accord 
cited  above  at  20  degrees.  The  third  day  at  25  c 

sorn 
;”  c( 
id  nc 
lat  1 
gern 

lOE 

tits 
wi  t? 
egre 

ha 
)rn 
)t 
lig 
iin 
it, 
ob 
i t 
es 

d 

8 

be- 

ll 

a- 

hos 

56 

-16- 


shows  19,  12,  and  no  "r  p's”  for  the  "19.2%"  and  "6.1%"  corn, 
respectively.  The  order  changes  in  favor  of  the  "12.6%" 
corn  on  the  fourth  day.  The  readings  have  not  been  con- 
tinued long  enough  to  indicate  whether  the  "r  p"  produc- 
tion would  finally  swing  to  the  drier  corn,  but  the  data 
taken  the  eighteen  day  at  20  degrees  suggest  such  a pos- 
sibility. There  is  also  some  very  good  evidence  brought 
out  in  this  table  to  lead  to  the  conclusion  that  corn  con- 
taining a3  little  as  6.1%  qioisture  is  too  dry  for  strong 
100  percent  vitality,  and  that  corn  having  as  much  moisture 
as  19.1  per  cent  is  too  moist  for  best  germination,  al- 
though the  development  of  the  embryos  that  are  viable,  is 
rapid. 

Moisture  in  seeds  is  commonly  considered  the  most 
influential  factor  in  determining  the  life  processes  going 
on  within  them.  It  would  seem  that  with  "6.1%"  corn  desic- 
cation had  progressed  so  far  that  life  activity  was  mater- 
ially reduced  making  renewal  of  these  functions  tardy  and 
in  some  of  the  seeds  difficult  or  impossible.  The  "19.2%" 
corn  has  been  carrying  on  rapid  respiration  for  so  long 
that  it  is  weakened  and  many  of  the  germs  are  dead.  The 
initial  germinative  processes  are  rapid,  but  the  value  of 
this  corn  for  seed  purposes  is  not  nearly  as  great  as  that 
of  the  ”12.6%"  corn. 

Composition  of  the  Corn  Kernel  and 
Its  Water  Absorption 

Pour  ears  of  the  Illinois  High  Oil,  Illinois  Low 
vil,  Illinois  High  Protein  and  the  Illinois  Low  Protein 


' 


. 

f 

. 

« 

r 

, 

• 

* 

. 

• 

* 

r 

-17- 


were  obtained  of  Mr.  Louis  Hunter  of  the  Plant  Breeding  Livi-’ 
sion.  Prom  the  high  and  low  oil  ears  three  rows  of  kernels 
from  each  ear  had  been  taken  for  an  analytical  determination 
of  the  percentage  of  oil.  The  high  and  low  protein  corn 
had  been  sampled  similarly  for  protein  determination.  The 
results  of  these  analyses  show  wide  extremes  in  kernel  com- 
position. 

Table  V.  Percentage  of  Protein  and  Oil  in  Lars  of  Extreme 
Types  with  respect  to  these  Constituents. 


Ear  No. 

Type 

Moisture 

Content 

Percentage 

Protein 

Percentag 

Oil 

e Averag 

15 

High 

Oil 

8.14 

- 

9.51 

36 

u 

ii 

6.84 

- 

9.11 

(Oil) 

41 

ii 

ii 

7.09 

- 

9.61 

91 

ft 

ii 

7.26 

- 

9.38 

9.40 

26 

Low 

Oil 

8.49 

- 

1.83 

33 

TT 

ii 

8.81 

- 

1.90 

(Oil) 

73 

ii 

?? 

8.19 

- 

1.62 

102 

ii 

ft 

10.04 

- 

1.73 

1.82 

19 

High 

Protein 

6.85 

5.15 

- 

26 

Tt 

ii 

7.02 

14.26 

- 

(Pro- 
t ain) 

47 

ii 

!? 

5.87 

15.90 

- 

69 

ii 

it 

7.26 

15.56 

L5.29 

3 

Low  Protein 

7.00 

6.50 

22 

ii 

T? 

7.35 

5.90 

(Pro- 
t ain) 

25 

ii 

ii 

8.30 

6.00 

- 

96 

tr 

ft 

7.85 

5.98 

_ _ J j 

>,095 

-18- 


The  high  oil  corn  contained  5.16  times  as  much  oil 

as  the  low  oil  strain,  while  the  protein  content  of  the 

high  type  was  £.18  times  that  of  the  low.  Twenty-five 

kernels  in  duplicate  from  each  ear  were  soaked  in  water 

for  £4  hours.  The  results  obtained  appear  below. 

Table  VI.  Imbibition  in  Corn  from  Individual  .Ears  of 
Special  High  and  low  Oil,  and  High  and  Low 
Protein  Corn. 


Type 

Ear 

Ho. 

Percentage 

water  in  the 
in  water  at 

corn  after  soaking 

5 

10 

15 

20 

25 

30°  C 

High 

Oil 

15 

38.52 

40.02 

45.45 

49.10 

50.76 

50.57 

IT 

it 

36 

32.76 

38.00 

44.65 

46.53 

4 7.90 

50.63 

II 

»? 

41 

38.36 

41.21 

45.50 

49.66 

52.41 

56.00 

tt 

it 

91 

34.17 

37.85 

45.14 

48.91 

50.33 

53.47 

low 

Oil 

26 

40.66 

42.08 

45.54 

50.67 

52.69 

54.19 

If 

ii 

33 

33.15 

37.71 

43.24 

46.72 

48.93 

50.51 

It 

T! 

73 

30.65 

33. 64 

41.08 

43.68 

45.06 

47.59 

it 

• It 

102 

33.85 

39.28 

45.25 

50.28 

50.59 

52.83 

High 
Prote in 

19 

28.82 

31.33 

35.84 

41.58 

43.47 

45.47 

it 

ft 

26 

30.96 

30.71 

39.29 

43.12 

46.80 

48.29 

>1 

ff 

47 

26.82 

30.01 

35.01 

41.47 

44.20 

46.05 

i» 

It 

69 

30.09 

34.55 

39.74 

44.93 

45.55 

47.21 

low 

Protein 

3 

34.91 

40.14 

43.91 

47.82 

49.75 

51.38 

n 

II 

22 

36.02 

39.21 

46.07 

50.48 

55.  79 

58.64 

it 

11 

25 

35.82 

39.09 

44.59 

48.25 

49.45 

57.80 

i? 

II 

96 

37.39 

39.59 

44.98 

48.68 

52.78 

53.82 

. I 


r» 


19- 


iJars  number  15  and  41  of  the  high  oil  series  are 
consistently  higher  in  water  content,  than  the  others,  with 
the  single  exception  of  ear  number  91  at  30°C.  har  ”36” 
is  rather  uniformly  lower  in  water  intake  than  the  other 
three  in  this  group.  It  is  also  slightly  lower  in  oil 
content,  and  somewhat  lower  in  original  moisture.  While 
the  results  are  not  conclusive,  they  are  suggestive  that 
slight  increased  quantities  of  oil  in  corn  is  associated 
with  greater  water  absorption.  Practically  all  the  oil  in 
corn  is  located  in  the  germ  region.  High  oil  corn  pos- 
sesses a very  large  germ  in  proportion  to  endosperm.  It 
is  presumably  the  rapid  intake  of  water  by  the  large  germs 
that  gives  the  higher  imbibi ti onal  curve  for  the  high  oil 
corn. 

With  the  low  oil  corn,  the  correlation  between  orig- 
inal moisture  content  or  slight  variations  in  oil  percentage, 
and  quantity  of  water  absorbed  does  not  seem  to  be  signi- 
ficant. The  differences  that  appear  at  five  degrees  carry 
through  uniformly  with  but  few  exceptions.  The  fluctuations 
between  corn  of  so  nearly  the  same  composition  in  respect  to 
oil  must  be  due  to  unknown  individual  ear  variations. 

It  will  be  noted  that  our  ear  number  26  which  is  more 
than  one  per  cent  lower  in  protein  than  its  three  compan- 
ions, has  absorbed  slightly  more  water  than  the  others,  har 
number  47  which  is  highest  in  protein  has  imbibed  the  least 
amount  of  water  at  four  of  the  six  temperatures.  High  pro- 
tein even  when  differences  are  very  slight,  appears  to 
hinder  water  absorption.  Since  ear  number  47  is  the  lowest 


- 


-20- 


in  originai  moisture  content  and  the  highest  in  protein 
composition  it  would  seem  that  the  presence  of  protein 
favors  dee  legation. 

Low  protein  ear  number  22  is  the  lowest  in  protein 
content  and  the  highest  in  water  content  at  four  of  the 
six  temperatures.  kar  number  3 is  the  highest  in  protein 
of  any  of  the  ears  of  the  low  protein  group,  and  is  the 
lowest  in  absorption  in  two-thirds  of  the  trials. 

In  order  to  present  more  clearly  the  performances 
of  each  of  the  four  groups  of  corn  the  data  from  the  indi- 
vidual ears  have  been  averaged  and  are  shown  in  Table  VII 
and  Graph  II. 

Table  VII.  Average  of  Imbibitional  Lata  from  High  and  Low 
Oil  and  High  and  Low  Protein  Corn. 


Type 

Percentage  wa 

ter  in  the  corn  after  soaking 
in  water  at 

Aver- 

age 

5 

10 

15 

20 

25 

30°C 

High  Oil 

35.95 

39.27 

45.19 

44.55 

50.35 

52.92 

45.37 

Low  Oil 

34.58 

38.18 

43.78 

47.84 

49.29 

50.03 

43. 95 

High  Protein 

29.17 

31.90 

37.47 

42.78 

45.01 

46.76 

38.85 

Low  Protein 

36.04 

39.51 

44.89 

48.80 

51.94 

55.41 

49.10 

The  low  oil  corn  possesses  a much  larger  proportion 


of  endosperm  than  does  the  high  oil  strain.  The  starches 
and  sugars  of  this  part  of  the  kernel  take  up  water  almost 
as  rapidly  as  the  unusually  large  germs  of  the  high  oil 
corn.  In  the  high  protein  com,  the  protein  is  carried 
largely  in  the  aleurone  layer  and  in  the  horny  starch 


' 


-21- 


around  the  outer  walls  of  the  endosperm.  This  serves  as 
a semi-impervious  layer  around  the  soft  starchy  portion  within, 
and  protects  the  germ  from  contact  with  water  except  from 

one  side.  The  low  protein  corn  contains  a much  larger 

tis.sue 

proportion  of  soft  starch^with  very  little  and  often  none 
of  the  horny  tissue  surrounding  it.  This  permits  ready 
intake  of  water. 

The  germination  of  this  corn  on  plaster  of  Paris 
blocks  at  20,  25,  and  30°  temperatures  shows  results  some- 
what different  from  those  obtained  in  water  absroption 
studies.  The  detailed  notes  concerning  the  germination 
appear  below  in  Table  VIII.  The  type  of  corn  is  indicated 
by  the  initial  of  the  strain  name  as  "L.O."  for  Low  Oil, 

H.r ."  for  High  Protein,  etc.  The  percentage  number  of 
kernels  that  had  produced  radicles  is  indicated  by  "r"; 
both  radicles  and  plumules  by  "r  p”;  seminal  roots  by 
Ms  r";  leaf  emergence  through  the  coleoptile  by  "le" ; 
plumules  that  were  produced  without  radicles  by  wp” ; and 
the  average  length  of  the  plumule  in  inches  by  "p  1”. 


-22- 

Table  VIII.  Germination  of  High  and  Low  Oil  and  High 
and  Low  Protein  Corn  at  20,  25  and  30°  C. 


' I)e-~ ' 

20° 

Is5 

’ ■ — 

30° 

Time 

vel- 

?|Tne 

( Days ) 

op- 

LO 

pn 

J 1 1 

1 ( 

J H 

o i : 

m 

? L *( 

3 H( 

HP 

H~P 

.Kent, . . 



__  m ^ t 

, _ u _ 

2 

r 

0 

0 

0 

0 

0 

0 

3 

0 

0 

6 

0 

0 

r 

0 

0 

0 

0 

0 

24 

70 

75 

37 

31 

58_ 

68 

3 

rp 

0 

0 

0 

0 

0 

12 

3 

3 

3 

46 

20 

18 

sr 

0 

0 

0 

0 

0 

6 

3 

0 

0 

30 

3 

3 

r 

0 

0 

0 

0 

49 

*27" 

40 

18 

45 

0 

'48 

18 

4 

rp 

0 

0 

0 

0 

0 

73 

58 

82 

37 

94 

45 

83 

rs 

0 

0 

0 

0 

0 

45 

26 

50 

25 

86 

25 

73 

r 

0 

u 

' <r 

’~"STT 

“O' 

' IT 

tr 

"‘IT 

"~U 

20 

— 0~“ 

5 

rp 

0 

0 

0 

0 

20 

100 

93 

100 

69 

94 

80 

100 

sr 

0 

_ 0 

0 

0 

6 

97 

95 

90 

60 

94 

73 

98 

r 

0 

0 

0 

0 

26 

0 

0 

0 

3 

3 

18 

0 

6 

rp 

0 

0 

0 

0 

49 

100 

100 

100 

80 

91 

80 

100 

sr 

0 

0 

0 

0 

40 

100 

100 

100 

91 

94 

73 

100 

__ — . 

le 

0 

0 

0 

0 

0 

6 

5 

13 

9 

37 

5 

40 

r 

0 

0 

0 

0 

3 

0 

0 

0 

3 

3 

~To~ 

0 

7 

rp 

0 

0 

0 

0 

74 

100 

100 

100 

80 

91 

88 

100 

sr 

0 

0 

0 

0 

74 

100 

100 

100 

80 

94 

85 

100 

le 

0 

0 

0 

0 

3 

30 

45 

83 

31 

74 

33 

80 

r 

0 

3 

10 

0 

3 

0 

0 

0 

3 

3 

5 

0 

8 

rp 

0 

0 

0 

0 

74 

100 

100 

100 

83 

91 

93 

100 

sr 

0 

0 

0 

0 

74 

100 

100 

100 

80 

94 

85 

100 

le 

0 

0 

0 

0 

6 

88 

70 

93 

60 

77 

83 

93 

r 

0 

27 

48 

8 

6 

0 

0 

0 

0 

3 

0 

0 

10 

rp 

0 

0 

0 

0 

77 

100 

98 

100 

86 

83 

95 

100 

sr 

0 

0 

0 

0 

83 

100 

100 

100 

83 

89 

88 

100 

le 

0 

0 

0 

0 

40 

97 

90 

95 

74 

80 

75 

100 

P 

0 

0 

0 

0 

9 

0 

3 

0 

6 

6 

0 

0 

pit  in. ) 

— 

— 

— 

- 

4.9 

5.9 

4.9 

7.5 

6.0 

8.7 

4.9 

9.1 

r 

0 

27 

58 

8 

rp 

0 

0 

5 

0 

12 

sr 

0 

0 

3 

0 

le 

0 

0 

0 

0 

r 

50 

38 

- - 

• - - - — 

rp 

0 

42 

43 

40 

18 

sr 

0 

12 

13 

8 

le 

0 

0 

5 

0 

r 

9 

27 

35 

23 

rp 

0 

67 

60 

50 

24 

sr 

0 

45 

23 

30 

le 

0 

15 

13 

8 

P 

0 

3 

0 

0 

pi  (in) 

0 

1.3  : 

L. 3 ] 

L.2 

, 


. 


-23- 


It  will  be  noted  that  the  High  Oil  corn  germinated 
more  rapidly,  had  a higher  total  vitality,  and  produced 
plumules  of  greater  length  than  that  of  the  Low  Oil  type. 
This  is  particularly  notidfcble  at  20  degrees.  The  differ- 
ence in  germination  is  much  greater  than  would  be  suggested 
by  the  differences  in  water  absorption  of  these  two  corns. 
However,  since  the  germs  and  embryo  of  the  Low  Oil  kernels 
are  so  small,  it  is  reasonable  to  suppose  that  the  vitality 
and  vigor  of  this  corn  would  be  low. 

The  Low  Protein  corn  has  produced  more  radicles  in 
two  days  at  £5  degrees  than  has  the  High  Protein  corn.  At 
20  degrees  the  Low  Protein  is  ahead  of  the  High  Protein 
in  every  respect.  The  rapidity  of  germination  and  the 
speed  of  subsequent  growth  at  25  and  30  degrees  is  much 
greater,  however,  in  the  High  Protein  corn.  The  average 
length  of  the  High  Protein  plumules  is  86  per  cent  greater 
at  30  degrees  and  53  per  cent  greater  at  25  degrees  than 
that  of  the  Low  Protein  com.  Low  Protein  content  is  evi- 
dently a limiting  factor  in  seedling  development  following 
germination. 

Influence  of  Temperature  on  Water  Absorption 

The  lack  of  harmony  between  water  absorption  and 
germination  has  suggested  the  need  of  some  study  on  the 
rate  of  water  intake  by  corn  grain.  And  also  since  temper- 
ature is  so  fundamental  to  germination  it  was  desired  to 
see  if  this  influence  was  due  to  reduction  or  increase  in 
the  absorption  of  water.  Fifty  grains  of  corn  of  the  same 
composite  lot  were  soaked  in  distilled  water  at  five  con- 


urve  1 


Kernels 


Tempe  rat 


Diff  erent 


u res 


20  l\  It  25  24  23  67 


l 

} ua  n titv  of 

ol  C 

o r n at 

-24- 


stant  temperatures  and  weighed  every  hour  for  24  and  then 
again  at  the  end  of  29  and  67  hours.  The  quantity  of 
water  taken  up  during  each  interval  appears  below  in 
Table  IX  and  in  Curve  I. 

Table  IX.  Rate  of  water  absorption  by  corn  at  five  con- 
stant temperatures. 


Time 
( Hours ) 

Increase  in  weight  of  fifty  grains  of  corn  as 
the  result  of  soaking  in  distilled  water  at- 

ICJO 

15^ 

20° 

25u 

grams 

grams 

grams 

grams 

grams 

1 

2.76 

2.53 

2.83 

2.00 

2.58 

2 

3.72 

3.41 

3.83 

4.14 

4.  54 

3 

4.41 

4.07 

4.72 

4.90 

5.34 

4 

5.22 

4.79 

5.50 

5.66 

6.23 

5 

5.67 

5.39 

5.92 

6.15 

6.71 

6 

6.11 

5.68 

6.68 

6.80 

7.32 

7 

6.49 

6.42 

7.04 

7.22 

7.73 

8 

6.86 

6.79 

7.45 

7.57 

7.83 

10 

7.29 

7.27 

8.04 

8.16 

8.54 

11 

7.47 

7.52 

8.33 

8.46 

8.84 

12 

7.71 

7.77 

8.57 

8.67 

9.05 

13 

7.70 

7.80 

8.73 

8.83 

9.13 

14 

7.88 

8.01 

8.86 

8.93 

9.21 

15 

8.06 

8.18 

9.01 

9.08 

9.43 

16 

8.22 

8.37 

9.23 

9.25 

9.48 

17 

8.34 

8.53 

9.39 

9.37 

9.62 

18 

8.60 

8.81 

9.65 

9.58 

9.80 

19 

8.61 

8.70 

9.74 

9.65 

9.91 

20 

8.76 

8.96 

10.00 

9.91 

10.13 

21 

8.98 

9.15 

10.02 

10.14 

10.39 

22 

9.09 

9.29 

10.28 

10.18 

10.41 

23 

9.19 

9.47 

10.35 

10.25 

10.46 

24 

9.24 

9.50 

10.44 

10.31 

10.58 

IT 

975T" 

~3790 

10.76 

10.81 

67 

10.89 

11.28 

12.13 

12.14 

12.32 

Water  is  taken  up  very  rapidly  during  the  first 


few  hours.  After  the  tenth  or  eleventh  hour  the  curve 
slightly  flattens  until  the  end  of  the  twenty-first 
hour,  when  its  upward  climb  is  further  reduced.  The 
curves  for  all  the  temperatures  run  in  the  same  general 
direction  with  only  slight  differences  in  angle.  Curves 
for  10  and  15,  and  for  20  and  25  degrees  are  quite 


-25- 


noticeably  paired.  The  wide  differences  in  germination 
that  have  been  brought  about  by  temperature  can  hardly  be 
accounted  for  by  differences  in  water  absorption.  The 
corn  at  10  degrees  absorbed  approximately  the  same  amount 
of  water  in  24  hours  as  that  at  30  degrees  did  in  12  hours. 
If  water  is  the  primary  essential  in  germination,  corn  at 
10  degrees  should  make  as  much  growth  in  10  days  as  that 
at  30  degrees  does  in  5 days.  The  germination  data  pre- 
sented previously  show  that  there  are  greater  differences 
than  these,  occurring  between  20  and  25  degrees. 

Two  Types  and  Two  Varieties  of  Corn  Soaked  in 
Water  at  Five  Constant  Temperatures  and  for 
Four  Different  Periods  and  Planted  in  the 
Field  for  Performance  Studies. 

Field  practice  has  indicated  that  two  or  three  days 
in  the  growth  of  corn  may  be  gained  by  soaking  the  seed 
in  water  for  a time  before  planting.  Director  Russell  of 

n 

the  Kothamsted  Experiment  Station  is  quoted  as  saying 
in  connection  with  an  explanation  for  the  frequent  benefit 
obtained  from  treating  seeds  electrolyt ically  that  kiln 
dried  barley,  especially  after  steeping,  will  germinate 
more  evenly  and  satisfactorily  than  will  ordinary  barley. 
This  is  particularly  the  case  if  the  barley  contains  any 
amount  of  moisture  over  14  or  15  per  cent.  The  soaking  of 
wheat  and  barley  as  a part  of  the  treatment  for  the  con- 
trol of  loose  smut  disease  is  a common  practice. 

Just  how  long  the  soaking  should  be  continued,  and 
at  what  temperature,  has  never  been  hinted  at.  Waister's9 


, 


• . 


• 

: 

. < 

* 

• 


C 

* 

. 


-26- 


work  with  barley  has  suggested  the  possibility  that  low 
temperature  may  be  more  desirable  than  high.  Corn  that 
had  been  germinated  by  Mr.  J.  H.  Holbert,  Pathologist, 

United  States  Department  of  Agriculture,  and  classified  into 
diseased  and  disease-free  groups  from  the  stand  point  of 
the  corn  rot  diseases  was  chosen  to  be  used  in  an  experiment 
planned  to  furnish  some  information  on  the  question  of 
benefits  from  soaking  seed  corn.  Moisture  tests  were  made 
on  each  of  the  four  corns  with  the  following  results: 

Table  X.  Moisture  Determination  of  Pour  Air  dry  Samples 
of  Corn. 


Variety 

Disease  condition 

Per  cent  moisture 

Punk's  90-Day 

Disease-free 

9.0 

Punk's  90-Day 

Diseased 

9.2 

Reid's  Yellow  Dent 

Disease-free 

10.8 

Reid's  Yellow  Dent 

Diseased 

9.5 

One  hundred  kernel  samples  of  each  of  the  above 


four  types  of  corn  were  soaked  for  12,  24,  36,  and  48  hours 
respectively,  at  each  of  10,  16,  20,  25,  and  30°  tempera- 
tures. Determinations  were  made  of  the  percentage  of  water 
absorbed.  These  results  appear  in  Table  XI. 


. 

t . 


. 


. 


. 


. - 


' 


. 


f ( f f 


-27- 


Table  XI.  Absorption  by  disease-free  and  diseased  Funk's 

Ninety  Day;  and  disease-free  and  diseased  Reid's 
Yellow  Dent  Corn. 


Time 
( Hours ) 

Corn 

10 

15 

20 

26 

30 

Funk's  D.F. 

32.08 

35.52 

37.14 

38.32 

45.76 

Funk's  D. 

34.93 

39.68 

42.83 

44.67 

46.86 

12 

Reid's  D.F. 

34.99 

36.90 

40.45 

42.43 

44.36 

Reid's  D. 

36  • 68 

40.39 

46.24 

44.90 

47.21 

Funk’s  D.F. 

38.37 

42.20 

46.89 

48.12 

48.97 

Funk's  D. 

41.36 

49.59 

50. 64 

52.96 

67.70 

24 

Reid's  D.F. 

40.94 

46.58 

48.17 

50.01 

50.83 

Reid's  D. 

42.00 

49.32 

52.10 

53.85 

57.79 

Funk's  D.  F. 

42.94 

47.31 

50.45 

52.50 

31.14 

Funk's  D. 

46.57 

53.21 

53.87 

57.54 

61.00 

36 

Reid's  D.  F. 

44.51 

50.27 

50.44 

56.33 

55.30 

Reid's  D. 

47.34 

53.91 

53.45 

38.61 

61.62 

Funk's  D.F. 

46.54 

49.80 

51.87 

55.24 

57.59 

Funk's  D. 

51.13 

59.24 

59.11 

63.10 

68.64 

48 

Reid's  D.F. 

52.51 

53.11 

54.30 

56.24 

60.40 

Reid's  D. 

50.49 

58.01 

57.68 

60.94 

63.85 

The  diseased  corn  in  39  cases  out  of  the  forty 


absorbed  more  water  than  the  disease-free  corn.  This 
fact  may  be  more  easily  seen  in  the  following  table  in 
which  the  average  percentage  water  of  imbibition  is  given 
for  the  disease-free  and  the  diseased  corn  of  both  varie- 
ties, separately: 


-28- 


Table  XII.  Average  water  absorption  by  disease-free  and 
diseased  corn. 


Variety 

Condition 

Average  per  cent 
water  imbibed 

Funk's  Yellow  Dent 

Disease  -free 

46.04 

Funk's  Yellow  Dent 

Diseased 

51.73 

Reid's  Yellow  Dent 

Disease-free 

48.46 

Reid's  Yellow  Dent 

Diseased 

51.76 

The  above  figures  suggest  that  the  disease-free 
corn  absorbs  water  less  readily  than  diseased  corn.  If 
this  is  the  case,  the  two  diseased  strains  of  corn  are 
practically  equal  in  regard  to  the  diseased  condition, 
but  of  the  disease-free  strains  the  Punk's  Yellow  Dent  is 
the  superior,  since  it  absorbed  less  water  under  the  same 
conditions  than  the  companion  strain  of  Reid's  Yellow 
Dent . 

In  order  to  learn  the  influence  of  temperature  on 

water  absorption  by  diseased  and  disease-free  corn,  the 

imbibition  percentages  of  both  these  strains  were  averaged. 

Table  XIII.  Relation  of  Temperature  to  Imbibition  in 
Diseased  and  Disease-free  corn. 


Temperature 

Percentage  Imbibition  on  water  free 
basis  by 

Diseased  corn 

Disease-free  corn 

Difference 

10 

43.150 

- 4x;5T 

15 

50.42 

45.46 

4.96 

20 

51.86 

47.46 

4.40 

25 

54.57 

49.90 

4.67 

30 

00 

o 

• 

CO 

tO 

51.79 

6.29 

' 

' 

' 


, 


, 


-29- 


watar  by 

It  will  be  noted  that  the  absorption  of/ diseased 
and  disease-free  corn  is  much  more  marked  at  15°  G than 
at  10°  C.  At  30°  C there  is  another  marked  acceleration 
in  the  rate  of  water  intake  in  the  diseased  corn.  The 
disease-free  corn  is  much  more  horny  in  composition  than 
the  diseased  corn,  which  contains  a high  proportion  of 
white  starch.  These  results  harmonize  with  the  data  ob- 
tained with  the  High  and  Low  Protein  varieties. 

The  disease-free  kernels  are  heavier  than  those 
from  the  diseased  ears.  The  average  weight  of  the  disease- 
free  grains  of  the  Punk's  90-day  corn  was  .29  grams  and  that 
of  the  diseased  kernels  .26  grams.  The  kernels  of  the  di- 
sease-free and  diseased  strains  of  Reid's  Yellow  Dent  corn 
weighed  .36  and  .31  grams  respectively. 

The  com  that  was  used  in  the  imbibition  studies, 
after  removing  the  surface  water,  was  taken  immediately  in 
covered  jars  to  the  field  where  it  was  planted  on  May  29* 

The  corn  representing  each  variety,  condition  and  treatment 
was  planted  separately.  Three  grains  were  planted  per 
hill  by  using  the  hand  drop  planter.  The  rows  were  fifteen 
hills  long.  Three  check  rows  were  planted,  one  on  each 
side,  and  one  in  the  center  of  the  field.  Only  two  of  the 
check  rows  could  be  used,  however,  in  calculating  th&se 
data  because  the  north  row  was  badly  damaged  by  gophers. 

Notes  on  stand,  sturdiness  of  plants,  rate  of 
growth,  production  of  suckers,  number  of  nubbins  and  good 
ears,  occurrence  of  leaning  and  down  plants,  and  develop- 
ment of  smut,  were  taken  during  the  season.  Since  the 


- 


* 

— 

. 

, 

• 

1 

- 


- 


' 


. 


. 


. 


t 


. 

, 

. 

, 


-30- 


data  thug  gathered  do  not  show  significant  differences  one 
way  or  the  other  for  the  time  and  temperature  of  presoaking 
of  the  seed,  the  tabulation  of  these  is  omitted  from  this 
paper. 

It  became  necessary  to  destroy  the  Heid's  Yellow 
Dent  Corn  in  this  experiment  before  pollination  in  order  to 
preserve  the  purity  of  some  valuable  pure  line  corn  growing 
near  by. 

The  yield  data  of  Funk's  ninety  Day  corn  appear 
below  in  Table  XIV. 


° 

- 


‘ 

« 


-31- 


Table  XIV.  Yield,  data  of  corn  in  the  presoaking  experiment. 


Time 
soaking 
( hours ) 

Temper- 

ature 

Disease-free 

Diseased 

Marketable 

Unmarketable 

Marketable 

Unmarketable 

Hone 

Check 

CD 

« 

CD 

11.3 

58.9 

12.4 

12 

10 

69.4 

13.1 

74.1 

16.0 

12 

15 

75.0 

12.5 

67.3 

9.9 

12 

20 

72.3 

10.0 

72.7 

13.2 

12 

25 

67.6 

11.8 

68.9 

14.1 

12 

30 

92.8 

9.9 

87.1 

15.0 

24 

10 

64.7 

14.5 

67.5 

13.1 

24 

15 

86.0 

13.1 

CD 

« 

to 

9.3 

24 

20 

68.3 

14.5 

58.3 

10.1 

24 

25 

68.8 

15.4 

81.1 

16.3 

24 

30 

80.8 

7.0 

84.6 

12.3 

Hone 

Check 

81.4 

15.5 

73.2 

17.2 

36 

10 

99.8 

12.2 

62.7 

13.1 

36 

15 

75.2 

15.4 

77,6 

12.2 

36 

20 

84.0 

12.8 

56.7 

10.0 

36 

25 

75.9 

10.0 

78.6 

13.1 

36 

30 

83.2 

10.9 

61.5 

14.3 

48 

10 

74.9 

8.1 

89.4 

8.1 

48 

15 

87.6 

6.2 

57.3 

10.0 

48 

20 

66.0 

9.1 

81.9 

12.9 

48 

25 

85.3 

7.0 

78.0 

8.0 

48 

30 

26.2 

7.1 

61.0 

8.0 

Average 

75.6 

11.3 

70.9 

11.7 

-32- 


The  average  yield  of  the  disease-free  corn  is 
almost  five  bushels  in  excess  of  the  diseased  corn.  The 
soaking  at  various  temperatures  do&^iot  show  consistent  dif- 
ferences. The  conclusion  from  this  work  can  only  be  that 
pre-soaking  seed  corn  has  no  effect,  either  beneficial  or 
otherwise,  on  the  performance  of  corn  in  the  field  under 
the  conditions  of  the  experiment.  It  is  quite  possible,  however, 
that  the  condition  of  the  soil  as  regards  moisture  content  at 
the  time  of  planting,  may  have  an  influence. 


- 

■ 


. 

A ,i 

. 

- 

r- 


. 


-33- 


V.  Conclusion 

The  data  obtained  in  these  investigations  suggest 

that : 

1.  Corn  harvested  in  the"milk"stage  is  capable  of 
more  rapid  water  absoiption  than  either  ’’dent”  or  ’’mature”  corn. 
Its  vitality  and  strength  of  germination  however  ars  less  than 
those  of  more  mature  corn. 

2*  Kernels  taken  from  the  field  when  in  the  "dent” 
stage  of  development  imbibe  less  water  than  those  harvested 
in  the  "milk"  stage  and  more  than  those  that  were  completely 
mature.  The  rate  of  germination  and  viability  is  intermedi- 
ate between  these  of  the  corn  harvested  in  the  early  and  late 
stages  of  development. 

3.  The  initial  moisture  in  corn  is  not  the  only  factor 
that  influences  the  quantity  of  water  absorbed  during  a twen- 
ty-four hour  period. 

4.  Corn  containing  6 per  cent  moisture  germinates  much 
slower  and  possesses  slightly  lower  vitality  than  that  har- 
vested in  the"dent"  stage.  A moisture  content  of  12  per  cent  is 
more  desirable  for  seed  corn  from  the  standpoint  of  vitality 
than  6 or  19,  although  corn  of  19  per  cent  moisture  germinates 
more  quickly. 

5.  High  Oil  corn  absorbs  more  water  during  a twenty- 
four  hour  period  than  Low  Oil  corn.  It  also  germinates  more 
rapidly  and  possesses  greater  viability  than  its  low  oil  com- 
panion. 

6.  Low  Protein  corn  imbibes  water  much  more  rapidly 

and  begins  the  germinative  process  sooner  than  the  High  Protein 


-34- 


corn.  Soon,  however,  it  is  overtaken  by  the  High  Protein 
type,  which  exceeds  it  in  gerrninational  vigor  and  vitality. 

7.  Water  absorption  by  corn  is  very  rapid  during  the 
first  few  hours  of  soaking.  The  rate  of  water  intake  gradu- 
ally grows  less,  until  some  point  quite  beyond  29  hours. 

Limit  ad 

8.  / imbibition  of  water  is  not  the  only  factor  retard- 
ing germination  at  low  temperatures.  Water  absorption  at 
low  temperatures  is  much  more  rapid  in  proportion  to  seedling 
growth  than  at  high  temperatures. 

9.  Diseased  corn  absorbs  water  more  rapidly  than  that 
which  is  disease-free. 

10.  The  soaking  of  seed  corn  in  water  at  different  tem- 
peratures for  various  periods  has  no  apparent  effect  upon 
field  growth  and  yield, 

VI.  Acknowledgements 

Grateful  acknowledgement  is  hereby  expressed  to 
Dr.  Charles  P.  Hottes,  under  whose  supervision  this  thesis  was 
prepared,  for  his  many  helpful  suggestions,  and  for  the  use 
of  his  splendidly  equipped  greenhouse  laboratory;  to  Dr. 

W.  L.  Burlison  for  his  inspiring  counsel  and  words  of  encour- 
agement, and  for  furnishing  some  of  the  materials;  and  to 
Mr.  Louis  Hunter  for  contributing  valuable  special  type  corn 
which  was  used  in  the  experiment. 


-35- 


VII.  References  Cited. 

1.  T.  A.  Kiesselbach  and  J.  A.  Ratcliff 

"Freezing  Injury  of  Seed  Corn"  Debr.  Res.  Bui.  16 
June  1920 

2.  Ewart,  A.  J. 

"On  the  Power  of  Withstanding  Desiccation  in  Plgnts" 

Proc.  Liverpool  Biological  Soc.  11 151-159.  1097. 

3.  Atkins,  W.R.G. 

"The  Absorption  of  Water  by  Seed3 

Sci.  Proc.  Roy  Dublin  Soc.  ra  ser.  12  (1909) 

Do.  4:35  - 46 

4.  Brown,  Adrian  J.  and  Worley  F.P. 

"The  Influence  of  Temperature  on  the  Absorption  of 
Water  by  seeds  of  Hordeum  vulgars  in  Relation  to 
Temperature  Coefficient  of  Chemical  Change" 

Proc.  Roy.  Soc.  of  London,  Series  B.  85:  546- 
553,  1912 

5.  Shull,  Charles,  A. 

"Temperature  and  nate  of  Moisture  Intake  in  Seeds" 

Bot.  Gaz.  69:  361  - 90.  May  1920 

6.  _____ 

"Increased  Yield  as  the  Result  of  Swelling  Seed  in 
Water" 

Ag.  J.  of  India  14:  816-  20  Oct.  1919 

J.  Bd.  Ag.  (Gt.  Brit.)  25;  1316  - 13  Feb.  1919 

7.  Darnell  - Smith  G.P. 

"The  Electrolytic  Treatment  of  Seeds  (Wolfryn  Process) 
before  Sowing" 

Ag.  Gaz.  11. S.  Wales  31:  393  - 95.  June,  1920 

8.  Braun,  H. 

"Presoak  Method  of  Seed  Treatment,  a Means  of  Pre- 
venting Seed  Injury  due  to  Chemical  Disinfectants 
and  of  Increasing  Germicidal  Efficiency". 

J.  Ag.  Res.  19:  363  - 92.  June  15,1921 

9.  Walster,  H.L. 

"Formative  Effect  of  High  and  Low  temperature  Upon 
Growth  of  Barley:  A Chemical  Correlation" 

Bot.  Gaz.  69:  97-126  . Feb.  1920 


